After a tremendous start to the season, Addison Russell went through a mighty slump in May. He seems to have mostly rebounded and has been well above average over his last 10 games. The chart below shows the extent of his slump and recovery. Let's see if we can find out what drove the slump and what has been fixed. And, unfortunately, what hasn't been.images/articles/2016-06-22/2016-06-22_20-36-53.png?i=220
As you can see above, Addison's 10 game moving average for wOBA (an excellent overall measure of offensive performance) bottomed out in game 55 and has been on the rise ever since. Let's first take a look at his walk and strikeout rates during this same time frame:images/articles/2016-06-22/2016-06-22_20-37-53.png
As you can see, his walk numbers have shot up along with his wOBA. It certainly looks like his discipline at the plate is highly correlated to his overall offensive performance. Let's take a deeper look at these numbers, though, to see what was driving the changing walk rates.images/articles/2016-06-22/2016-06-22_20-42-18.png?i=106
During his recovery, his swing percentages (O-Swing% is the percentage of times he swings at pitches outside the zone; Z-Swing% is the percentage of times he swings at pitches inside the zone) have definitely dropped, though they were starting to decline just before his performance bottomed out. The next thing to look at is what happened when he did swing:images/articles/2016-06-22/2016-06-22_20-43-01.png?i=173
This is where we start to see the real improvement! So he has gotten a little more selective at the plate, but he is also making a lot more contact when he does swing. During his slump, he had fallen way below his average contact rates on balls in the zone and on balls out of the zone. Basically, he was swinging and missing like 2014 Javy Baez. Well, not quite that bad, but it was still well below his normal performance.
The next question, though, is what kind of contact is he making?images/articles/2016-06-22/2016-06-22_20-39-57.png?i=696
When we look at the batted ball types, we see a lot of noise in the rolling 10 game samples. One of the things that obviously drove his slump is the massive shift in ground ball versus fly ball rates. Through the first 30+ games of the year, he was hitting nearly equal amounts of grounders and fly balls. Around game 38 this year, those two lines diverged dramatically and Addison became an extreme ground ball hitter.
So his slump was driven by a couple of factors at the same time: he wasn't making nearly as much contact and when he hit the ball, he hit it on the ground. That's a certain recipe for a deep dive in offensive performance.
There is actually one disturbing trend in his recovery: over the past 10 games Addison's line drive percentage has dropped dramatically. That may just be statistical noise, but it is something to keep an eye on as he tries to build on his recovery.
In addition to the type of contact, we can also look at the quality of contact.images/articles/2016-06-22/2016-06-22_20-40-56.png?i=984
This is really the final piece of the puzzle for the slump and the recovery. During his hot streak at the beginning of the year, Addison was hitting the ball hard with great frequency. Then, during the slump, his hard hit % dropped and his soft hit % actually rose above it for a while. During the recovery, his hard hit percentage has hovered around his average, but his soft hit percentage has plummeted. He has gone back to hitting the ball with much more authority.
So, to sum up, the slump in performance was driven by a lot of swings and misses and a lot of weak contact on ground balls. All of those factors have gotten much better over the past 15 or so games and generally continue to improve. But there is one area of performance that has still not gotten better:images/articles/2016-06-22/2016-06-22_20-38-30.png
As you can see, his strikeout numbers are still hovering in the 30-35% range. Hopefully that is just bad luck. Given the improvements in his contact rates both in the zone and out of the zone (and slight improvements in swing percentages), his strikeout rate should start to fall.
Overall, things are looking a lot better for Addison. There are a couple of things to watch for, but his performance is definitely looking better after his prolonged slump.
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